"I know how quick Lewis is and if his head is in the right place he will be unbeatable [in the title race]."

As for his own chances of success this season, the Drivers' Championship may be a step too far but Button feels race wins could yet be on the cards for McLaren.

He added: "It's been a very tough year. We're not at the front, where we're used to being but we're getting stronger. The British Grand Prix showed that as we qualified third in tricky conditions and almost got a podium.

"We've got the best engine, which is the Mercedes, so we don't have that excuse. We just haven't built a good enough car to win races this year. We're working hard though and there have been a lot of improvements already. We will win races it's just a matter of time.

"It is frustrating because when you have won races and a championship before, nothing else is good enough, but we're on the right track and that's the most important thing."